Breathing appliance



Dec. 11, 1934. R H, DAVlS BREATHING APPLIANCE 2 Sheets-Sheet 1 Filed Dec. 22, 1931 Dem 1934- R. H. DAVIS 1,934,113

BREATHING APPLIANCE Filed Dec. 22, 1951 2 Sheets-Sheet 2 Patented Dec. 11, 1934 UNITED starts PATENT" orrics 1,984,118 BREATHING APPLIANCE Robert Henry Davis, London, England Application neee ber'az, 1931, seria No. 582,622 In Great Britain October 14, 1931 3 Claims;

an inflatable envelope of rubber or the like, a

mouthpiece preferably having means whereby it may be attached to the head of the person wearing the appliance, a breathing tube connecting the mouthpiece and breathing bag, means for absorbing carbon dioxide from the exhaled air, and means for admitting a charge of oxygen to the interior of the breathing bag, for example, an oxygen cylinder forming a part of the appliance and provided with a valve controlled connection with the breathing bag.

It is a difiiculty with appliances of this type, that the wearer, when he reaches the surface of the water, may be in an unconscious condition or too unwell to close the shut-off valve of the breathing bag (usually provided in the mouth piece of the appliance) and thereby convert this bag into a-buoyancy chamber in the usual way (the wearer thereafter breathing from the open air instead of through the mouthpiece) and if not rescued in a' short time, may exhaust his supply of air and oxygen in the breathing bag, with the result that this bag may become so deflated as to be of insuiiicient buoyancy to keep the wearer afloat. Or, should the wearer be unconscious or dead when he reaches the surface the mouthpiece may become dislodged from his mouth and exposed to the sea, whereupon the breathing bag will simply flood, with complete loss of buoyancy to the appliance. In any of these contingencies, as will be appreciated, the person wearing the appliance will sink, without leaving any trace of his whereabouts, and this is regarded as a distinct drawback with existing forms of appliance of the type referred to.

The object of the present invention is to provide a modification of said existing forms of the appliance whereby this difficulty may in a simple and effective manner be met.

According to the present invention, a selfcontained breathing appliance of the type re ferred to comprises, in combination, and in the form of a complete pro-assembled unit, an inflatable'breathmg bag, a mouthpiece, a breathing tube connecting the mouthpiece and breathing bag, means for admitting a charge of respiratory gas to the breathing bag, means for absorbing carbon dioxide from the exhaled air, and a detachable inflatable buoyancy bag additional to the breathing bag and connected thereto or to a part of the appliance other than the breathing bag, for example, by body straps so as to hang against the back of the wearer of the appliance.

.As will be appreciated, the provision, as above, of an additional buoyancy chamber, provides in a simple manner against the contingencies re- 5' ferred to by serving to keep the wearer afloat even though he should, as stated, have exhausted the whole of his air and oxygen supply and thus the breathing bag should have become deflated and have lost its buoyancy, or, again, even if the breathing bag should have become flooded and for this reason have lost its buoyancy. Moreover, with the additional buoyancy bag, the wearer of the appliance has no need to conserve his oxygen supply to ensure that he has sufill5 cient to keep him afloat when he reaches the surface; he can use the whole of his oxygen for breathing purposes, relying on the additional buoyancy bag to keep him afloat.

The invention will now be further described with reference to the accompanying drawings, which illustrate two embodiments by way of example and in which:

Figure l is a front elevation of an appliance in accordance with the invention,

Figure 2 is a vertical transverse section through the appliance on the section line 2-2 of Figure 1,

and

Figures 3 and 4 show two forms respectively of a modifiedconstruction.

Like reference numerals indicate like parts in the various figures.

Referring to Figures 1 and 2, the appliance comprises a mouthpiece 10 connected by a flexible tube 11 to a breathing bag 12. The bag 12 is a rubber envelope to the bottom of which is attached bya strap fitting 13, a cylinder of compressed oxygen 14. The oxygen cylinder 14 is connected to the breathing bag envelope by a conduit 15 controlled by a valve 16. The conduit 15 terminates, within the interior of the breathing bag envelope, in a nozzle fitting 17 carrying a small capsule 18' of compressed oxygen. The capsule 18 has a slender hollow neck 19 by which the capsule may if necessary and in known manner be broken off from the 45 fitting 17 to release the gas within-the capsule.

[accommodated within the envelope 12 near the top thereof is a canister 20 packed with a substance capable of absorbing or combining with carbon dioxide. The exhaled air from the mouthpiece has to pass through this canister to enter the envelope and in doing so is deprived of its carbon dioxide content.

Detachably secured, for example, by small buttons or turn buckles 120, to the front of the envelope 12 is a second inflatable envelope 21 constituting the buoyancy chamber of the appliance in accordance with the invention.

This envelope 21 is of rubber and is provided with an inlet 22 at the top through which gas, for example, breath from the user of the appliance, may be blown directly into the envelope to inflate it.

The envelope 21 is also provided for its inflation with a capsule 23 of compressed gas, for example, air or oxygen, carried upon the inner face of a cap 24 screwed into and closing a socket 25 receiving it in the wall of the envelope.

If desired, either the inlet 22 or the capsule 23 (and its mounting) may be omitted, the envelope being arranged to be inflated solely by gas released from the capsule or solely by air blown into the said inlet, as the case may be.

The buoyancy chamber may also have fitted in its wall a non-return relief valve 25 for relieving the envelope of excess internal gas pressure. This valve may be of any convenient construction.

Figures 3 and 4 illustrate a modification of the invention according to which the buoyancy chamber 21 is attached, not to the breathing bag envelope as in the earlier construction, but to body straps 26, whereby it is caused to hang against the back (for example, behind the shoulders, as shown) of the wearer of the appliance.

The earlier construction, however, is generally to be preferred to this arrangement, as the position of the buoyancy chamber in that construction is such that the wearer, should he happen to be unconscious, is caused to float face uppermost.

The buoyancy chamber 21, in the arrangement shown in Figure 3, is provided for its inflation with an air inlet 22 which communicates, by means of a length of flexible tubing 27, with the mouthpiece 10 of the appliance. The mouthpiece 10 is fitted with a two-way valve 28 which establishes communication between the mouthpiece and the breathing bag 12 in one position, and between the mouthpiece and the envelope 21, in the other position. The buoyancy chamber may also be provided with a capsule 23 of compressed gas as in the other construction.

In the use of the appliance, the wearer may inflate his buoyancy chamber in either of two ways. according to desire or as circumstances permit, and either before he reaches the surface or after, again at will or as circumstances permit. Thus, if it is possible, he may inflate the chamber by exhalation through the inlet 21 before he leaves the submarine and reaches the open water, or after he reaches the surface; or, if this is impossible for any reason, for example, if the wearer has not had suflicient time before reaching the open water or a flooded compartment of the submarine through which he has to pass to reach the open water, to inflate the buoyancy chamber through the inlet 21, the chamber may be inflated simply by breaking off the compressed gas capsule 23. Again, if the wearer should for any reason have omitted to inflate his buoyancy chamber prior to reaching the open water, and should discover the fact upon reaching the surface, he may break his compressed gas capsule then and thereby inflate the chamber, without the necessity of removing the mouthpiece and thereby discontinuing breathing communication with the breathing bag.

The supplementary buoyancy chamber may, if desired, be secured to the breathing bag in such a manner that it is left loose below the point of attachment, so as to be capable of floating up to a point at which its buoyancy will be the most eiflcient.

In the alternative construction illustrated in Figure 4, the supplementary buoyancy chamber 21 is arranged to be inflated indirectly by gas admitted to it from the breathing bag 12 by way of a non-return valve 29 mounted upon the wall of the breathing bag and a length of flexible tubing 30.

It will be apparent that the invention is capable of wide variation as regards the precise form and position of the buoyancy chamber and in respect of other constructional details, without departure from the scope or spirit of the invention.

What I claim is:

1. A self-contained breathing appliance for submarine use, comprising in combination, an inflatable breathing bag, a mouthpiece, a breathing tube connecting the mouthpiece and breathing bag, means for admitting a charge of respiratory gas to the breathing bag, means for absorbing carbon dioxide from the exhaled air, an inflatable buoyancy bag, an inflation gas inlet to said buoyancy bag, a tube connecting said inlet to the mouthpiece and a two-way valve in the mouthpiece adapted to place the latter selectively into communication with the buoyancy bag or the breathing bag at will.

2. A self-contained breathing appliance for submarine use which comprises in combination an inflatable breathing bag, a mouthpiece, a breathing tube connecting the mouthpiece with the breathing bag, means for admitting a charge of respiratory gas to the breathing bag, means for absorbing exhaled carbon dioxide, an inflatable buoyancy chamber devoid of communication with the breathing bag, an inflation gas inlet to the buoyancy chamber, a tube connecting said inlet to the mouthpiece and a two-way valve in the mouthpiece adapted to place the latter selectively into communication with the buoyancy chamber or the breathing bag at will.

3. A self-contained breathing appliance for submarine use which comprises in combination aninflatable breathing bag, a mouthpiece, a breathing tube connecting the mouthpiece with the breathing bag, means for admitting a charge of respiratory gas to the breathing bag, means for absorbing exhaled carbon dioxide, an inflatable buoyancy chamber mounted upon the exterior of the breathing bag and devoid of communication therewith, an inflation gas inlet to the buoyancy chamber, a tube connecting said inlet to the mouthpiece and a two-way valve in the mouthpiece adapted to place the latter selectively into communication with the buoyancy chamber or the breathing bag at will.

ROBERT HENRY DAVIS. 

